Method and apparatus for managing packet data network connection on basis of local area in wireless communication system

ABSTRACT

A method and an apparatus for providing, setting, maintaining, and releasing a packet data network (PDN) connection on the basis of a local area in a wireless communication system are provided. The method includes receiving the PDN subscription information on the basis of the local area from a business operator server, inspecting whether the current location information for the terminal exists in the PDN subscription information on the basis of the local area, and starting a procedure for setting the PDN on the basis of the local area when the current location information exists therein.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a U.S. National Stage application under 35 U.S.C.§371 of an International application filed on Oct. 31, 2013 and assignedapplication number PCT/KR2013/009808, which claimed the benefit of aKorean patent application filed on Oct. 31, 2012 in the KoreanIntellectual Property Office and assigned Serial number 10-2012-0122706,the entire disclosure of which is hereby incorporated by reference.

TECHNICAL FIELD

The present disclosure relates to a structure and procedure of a LocalArea (LA) Packet Data Network (PDN). More particularly, the presentdisclosure relates to a method and apparatus for providing,establishing, maintaining, and releasing a PDN connection based on alocal area.

BACKGROUND

Wireless communication systems have been developed to provide broadbanddata service such as multimedia service in addition to traditional voiceservice. Despite limited communication resources, various types of dataservices are in demand. Therefore, a more advanced wirelesscommunication system is required.

To satisfy the demand, wireless communication systems that providePacket Data Network (PDN)-based enhanced services, such as a Long TermEvolution (LTE) system (or an Evolved Packet System (EPS)) proposed bythe 3 ^(rd) Generation Partnership Project 2 (3GPP2) have been deployedand have gained popularity.

A PDN may be deployed over a local area as well as a wide service areaand research on specific procedures for operating a PDN in a local areais needed.

The above information is presented as background information only toassist with an understanding of the present disclosure. No determinationhas been made, and no assertion is made, as to whether any of the abovemight be applicable as prior art with regard to the present disclosure.

SUMMARY

Aspects of the present disclosure are to address at least theabove-mentioned problems and/or disadvantages and to provide at leastthe advantages described below. Accordingly, an aspect of the presentdisclosure is to provide a method and apparatus for establishing a LocalArea (LA) Packet Data Network (PDN) connection in a wirelesscommunication system.

Another aspect of the present disclosure is to provide a method andapparatus for releasing an LA PDN connection in a wireless communicationsystem.

Another aspect of the present disclosure is to provide a method andapparatus for maintaining an LA PDN connection in a wirelesscommunication system.

Another aspect of the present disclosure is to provide a method andapparatus for reestablishing an LA PDN connection in a wirelesscommunication system.

In accordance with an aspect of the present disclosure, a method forestablishing a PDN connection by a User Equipment (UE) in a wirelesscommunication system is provided. The method includes receiving LA PDNsubscription information from an operator server, determining whethercurrent location information about the UE is included in the LA PDNsubscription information, and in the presence of the current locationinformation about the UE in the LA PDN subscription information,starting an LA PDN establishment procedure.

In accordance with another aspect of the present disclosure, a UE forestablishing a PDN connection in a wireless communication system isprovided. The UE includes a receiver configured to receive LA PDNsubscription information from an operator server, and a controllerconfigured to determine whether current location information about theUE is included in the LA PDN subscription information, and in thepresence of the current location information about the UE in the LA PDNsubscription information, to control starting of an LA PDN establishmentprocedure.

In accordance with another aspect of the present disclosure, a methodfor updating subscription information about a UE by a MobilityManagement Entity (MME) that manages mobility of the UE in a wirelesscommunication system is provided. The method includes, if LA PDNsubscription information about the UE is updated, receiving the updatedLA PDN subscription information from an operator server, determiningwhether current location information about the UE is included in an LAPDN context including a Tracking Area (TA) list of the UE, and in thepresence of the current location information about the UE in the LA PDNcontext, transmitting information indicating the update of the LA PDNsubscription information to the UE.

In accordance with another aspect of the present disclosure, an MME formanaging mobility of a UE in a wireless communication system isprovided. The MME includes a communication interface configured totransmit and receive messages for updating LA PDN subscriptioninformation, and a controller configured, if LA PDN subscriptioninformation about the UE is updated, to control reception of the updatedLA PDN subscription information from an operator server, to determinewhether current location information about the UE is included in an LAPDN context including a TA list of the UE, and in the presence of thecurrent location information about the UE in the LA PDN context, tocontrol transmission of information indicating the update of the LA PDNsubscription information to the UE.

In accordance with another aspect of the present disclosure, acommunication method of a Base Station (BS) during handover of a UEusing a PDN in a wireless communication system is provided. Thecommunication method includes, if the UE performs handover to a targetBS within an LA in a connected state, determining whether currentlocation information about the UE is included in an LA PDN context, andin the presence of the current location information about the UE in theLA PDN context, transmitting a handover request message including an LAPDN context related to the handover to the target BS.

In accordance with another aspect of the present disclosure, a BS forsupporting handover of a UE using a PDN in a wireless communicationsystem is provided. The BS includes a communication interface configuredto transmit and receive messages related to the handover of the UE, anda controller configured, if the UE performs handover to a target BSwithin an LA in a connected state, to determine whether current locationinformation about the UE is included in an LA PDN context, and in thepresence of the current location information about the UE in the LA PDNcontext, to transmit a handover request message including an LA PDNcontext related to the handover to the target BS.

In accordance with another aspect of the present disclosure, a methodfor releasing a PDN connection by an MME that manages mobility of a UEin a wireless communication system is provided. The method includesreceiving a Tracking Area Update (TAU) request from the UE, determiningwhether current location information about the UE is included in an LAPDN TA list, and in the absence of the current location informationabout the UE in the LA PDN TA list, starting an LA PDN disconnectionprocedure.

In accordance with another aspect of the present disclosure, a methodfor releasing a PDN connection by an MME that manages mobility of a UEin a wireless communication system is provided. The method includesdetermining whether current location information about the UE isincluded in an LA PDN TA list, and in the absence of the currentlocation information about the UE in the LA PDN TA list, maintaining anLA PDN context of the UE until expiration of an LA PDN context retaintimer.

In accordance with another aspect of the present disclosure, a methodfor reestablishing a PDN connection by an MME that manages mobility of aUE in a wireless communication system is provided. The method includesreceiving a service request message from the UE that returns to an LA,transmitting an initial context setup request message including an LAPDN context and an LA bearer context of the UE to a BS, and transmittinga bearer modify request for LA PDN reconnection of the UE to a servinggateway.

In accordance with another aspect of the present disclosure, a methodfor reestablishing a PDN connection by an MME that manages mobility of aUE in a wireless communication system is provided. The method includesreceiving a TAU request from the UE that performs handover in aconnected state from a source BS outside an LA to a target BS within theLA, determining whether current location information about the UE isincluded in an LA PDN context before expiration of an LA PDN contextretain timer, and in the presence of the current location informationabout the UE in the LA PDN context, transmitting to the target BS abearer setup request including an LA PDN context and a bearer context.

Other aspects, advantages, and salient features of the disclosure willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses various embodiments of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the present disclosure will be more apparent from thefollowing description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1A illustrates a wireless communication system that deploys a LocalArea (LA) Packet Data Network (PDN) according to an embodiment of thepresent disclosure;

FIG. 1B illustrates a configuration of LAs according to an embodiment ofthe present disclosure;

FIG. 2 is a diagram illustrating a signal flow for a procedure forupdating LA PDN subscription information in a wireless communicationsystem according to an embodiment of the present disclosure;

FIGS. 3A, 3B, and 3C are diagrams illustrating signal flows for atriggering method in an LA PDN establishment procedure in a wirelesscommunication system according to various embodiments of the presentdisclosure;

FIG. 4 is a diagram illustrating a signal flow for an LA PDNestablishment procedure according to an embodiment of the presentdisclosure;

FIG. 5 is a diagram illustrating a signal flow for a procedure fortransmitting an LA PDN context during X2 handover according to anembodiment of the present disclosure;

FIG. 6 is a diagram illustrating a signal flow for a procedure fortransmitting an LA PDN context during S1 handover according to anembodiment of the present disclosure;

FIG. 7 is a diagram illustrating a signal flow for an LA PDNdisconnection procedure according to an embodiment of the presentdisclosure;

FIG. 8 is a diagram illustrating a signal flow for a deferred LA PDNdisconnection procedure according to an embodiment of the presentdisclosure;

FIG. 9 is a diagram illustrating a signal flow for an LA PDNreconnection procedure according to an embodiment of the presentdisclosure;

FIG. 10 is a diagram illustrating a signal flow for an LA PDNreconnection procedure according to an embodiment of the presentdisclosure;

FIG. 11 is a block diagram of a User Equipment (UE) according to anembodiment of the present disclosure; and

FIG. 12 is a block diagram of an evolved Node B (eNB) according to anembodiment of the present disclosure.

Throughout the drawings, it should be noted that like reference numbersare used to depict the same or similar elements, features, andstructures.

DETAILED DESCRIPTION

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of variousembodiments of the present disclosure as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the various embodiments describedherein can be made without departing from the scope and spirit of thepresent disclosure. In addition, descriptions of well-known functionsand constructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of the presentdisclosure. Accordingly, it should be apparent to those skilled in theart that the following description of various embodiments of the presentdisclosure is provided for illustration purpose only and not for thepurpose of limiting the present disclosure as defined by the appendedclaims and their equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

In various embodiments of the present disclosure, a Packet Data Network(PDN) activated in a Local Area (LA) is defined as an LA PDN. The LAincludes tracking areas in which a packet data service is available andeach tracking area includes adjacent cells.

FIG. 1A illustrates a wireless communication system that deploys an LAPDN according to an embodiment of the present disclosure. The wirelesscommunication system illustrated in FIG. 1 is an LA PDN deployed, forexample, in a 3^(rd) Generation Partnership Project (3GPP) EvolvedPacket System (EPS). However, it is to be understood that the presentdisclosure may be deployed in any of various communication systems.

Referring to FIG. 1A, an operator server 100 is a server of acommunication operator or a service operator that provides a packet dataservice. A Home Subscriber Server (HSS) 200 manages authenticationinformation, subscription information, and service information about aUser Equipment (UE) 700. It is assumed that the UE 700 is any UEaccessing a PDN such as the Internet through a PDN GateWay (P-GW) like aServing GateWay (S-GW) 400 and a Local GateWay (L-GW) 500. The UE 700may communicate with other Internet Protocol (IP)-based communicationdevices (not shown) within a local network (that is, LA) 800 a bycreating a Local IP Area (LIPA) PDN connection through the L-GW 500.LIPA represents local IP access in an EPS. In an embodiment of thepresent disclosure, a LIPA PDN is an example of the LA PDN. However, itis to be clearly understood that the LA PDN of the present disclosure isnot limited to the LIPA PDN. In other words, the various embodiments ofthe present disclosure are applicable, for example, to various types ofwireless communication systems in which an L-GW may be located near toan evolved Node B (eNB) as well as to Selective IP Traffic Offloading(SIPTO) or LIPA described in3GPP TS 23.401.

In FIG. 1A, a Mobility Management Entity (MME) 300 is responsible formobility and location registration of the UE 700 and management of aTracking Area (TA) list for location management of the UE 700. The MME300 is also responsible for a control plane for exchanging controlinformation between the UE 700 and an Evolved Packet Core (EPC). Ifsubscription information about a UE (i.e., a user) in an LA PDN(referred to as “LA PDN subscription information”) is updated and thecurrent location of the UE 700 is included in an LA PDN context, the MME300 provides information indicating update of the LA PDN subscriptioninformation to the UE 700 in an embodiment of the present disclosure.

The EPC includes the MME 300, the S-GW 400, and the L-GW 500. The S-GW400 acts as a reference point that is not changed at a network sideduring handover. In other words, even though the UE 700 moves between aplurality of eNBs 600 (i.e., eNBs 600-1, 600-2 . . . 600-n), the S-GW400 is not changed. The S-GW 400 provides a data bearer for a packetdata service under the control of the MME 300. The L-GW 500 creates aLIPA PDN connection and assigns an IP address to the UE 500, uponrequest of the S-GW 400.

The eNBs 600 transmit messages used during procedures for establishing,maintaining, and releasing an LA PDN connection between the network andthe UE 700. If the UE 700 performs handover within an LA, an eNB 600checks whether current location information about the UE 700 is includedin an LA PDN context. In the presence of the current locationinformation about the UE 700, the eNB 600 provides an LA PDN contextrelated to the handover to a target eNB to which the UE 700 moves.

In an embodiment of the present disclosure illustrated in FIG. 1, it isassumed that other UEs (not shown) that do not use LIPA PDN connectionsuse a general packet data service in a service area 800 b other than anLA.

FIG. 1B illustrates a configuration of LAs according to an embodiment ofthe present disclosure.

Referring to FIG. 1B, one LA L1, L2, or L3 800 a may be configured perUE 700. One eNB eNB1 or eNB2 may configure a plurality of LAs. In FIG.1B, eNB1 configures two LAs L1 and L2 and eNB2 configures two LAs L2 andL3. An LA such as L2 may be configured to be overlapped betweendifferent eNBs eNB1 and eNB2.

After subscription information (that is, LA PDN subscriptioninformation) about a UE (i.e., a user) in a PDN (that is, an LA PDN)configured by adding the LAs 800 a to an existing PDN is initiallyprovided to the UE 700, the LA PDN subscription information may beupdated dynamically.

Hereinbelow, a description will be given of how an LA PDN is configuredinitially or dynamically, established, maintained during movement of theUE 700, and disconnected according to an embodiment of the presentdisclosure.

A procedure for initially providing LA PDN subscription informationaccording to an embodiment of the present disclosure will first bedescribed below.

LA PDN subscription information about a UE is stored in a UniversalSubscriber Identity Module (USIM) of the UE. The LA PDN subscriptioninformation includes at least one of a TA list, an LA Access Point Name(LA APN), an LA Identifier (LA ID), additional information, and existingPDN configuration data. The additional information may include an LAverbose name and an LA icon. Accordingly, LA PDN subscriptioninformation stored in the HSS 200 illustrated in FIG. 1A includes atleast one of a TA list, an LA APN, an LA ID, and existing PDNconfiguration data.

A procedure for dynamically updating LA PDN subscription data orinformation according to the present disclosure will be described below.

The operator server 100 illustrated in FIG. 1A may update the LA PDNsubscription information. If the MME 300 has an LA PDN context andcurrent location information about the UE is included in the LA PDNcontext, the MME 300 may transmit a message for triggering a procedurefor updating the LA PDN subscription information between the UE 700 andthe operator server 100.

If the LA PDN subscription information stored in the UE 700 has beenchanged, the operator server 100 may update the LA PDN subscriptioninformation to the changed LA PDN subscription information. The UE 700may request establishment or termination of an LA PDN connection to anetwork based on the updated LA PDN subscription information.

FIG. 2 is a diagram illustrating a signal flow for a procedure forupdating LA PDN subscription information in a wireless communicationsystem according to an embodiment of the present disclosure.

Referring to FIG. 2, the operator server 100 updates the LA PDNsubscription information about the UE 700 using the LA 800 a , stored inthe HSS 200 in operations 201 to 209. For example, if the LA PDNsubscription information about the UE 700 has been changed, the operatorserver 100 provides the updated LA PDN subscription information to theHSS 200 and the HSS 200 stores the updated LA PDN subscriptioninformation in operation 201. In operation 203, the HSS 200 transmitsthe updated LA PDN subscription information to the MME 300. Inoperations 201 and 203, the operator server 100 and the HSS 200 maytransmit only the updated LA PDN subscription information or entiresubscription information about the UE 700 including the LA PDNsubscription information.

The MME 300 determines whether current location information about the UE700 (for example, a current TA Indication (TAI) of the UE 700) ispresent in an LA PDN context managed by the MME 300 in operation 205.The LA PDN context includes an LA APN, a TA list, and existing LA PDNinformation.

The LA PDN subscription information about the UE 700 includes existingPDN information and information about an area in which a PDN connectionmay be created. This LA PDN subscription information includes an APN, anLA ID, a TA list, an LA verbose name, an LA icon, and existing PDNsubscription information. After receiving the updated LA PDNsubscription information, the UE 700 determines whether the TAIindicating the current location is included in the updated LA PDNsubscription information by checking the TAI indicating the currentlocation of the UE 700 and the updated LA PDN subscription information.If the TAI is included in the updated LA PDN subscription informationbut the UE 700 is not currently connected to any LA PDN, the UE 700 mayrequest creation of an LA PDN.

In an embodiment of the present disclosure, it is assumed that the LAPDN context includes the current location information about the UE 700.Subsequently, the MME 300 transmits information indicating that the LAPDN subscription information has been changed to the UE 700 in operation207 and transmits ACKnowledgement (ACK) information indicating that theMME 300 has received the updated LA PDN subscription information to theHSS 200 in operation 209. Operation 207 is performed so that the UE 700may initiate an Over The Air (OTA) connection with the operator server100 to receive the updated LA PDN subscription information. Operation207 is optional. Further, even though operation 207 is not performed,the UE 700 may periodically request the updated LA PDN subscriptioninformation to the network and receive it from the network.

In operation 211, the HSS 200 transmits confirmation informationindicating that the LA PDN subscription information about the UE 700 hasbeen updated to the operator server 100. The operator server 100transmits the LA PDN subscription information to the UE 700 through amobile communication network (OTA) in operation 213. In operation 215,the UE 700 determines whether the current location informationindicating the current location of the UE 700, for example, the currentTAI is included in the updated LA PDN subscription information receivedin operation 213.

In an embodiment of the present disclosure, it is assumed that thecurrent location information (TAI) is present in the updated LA PDNsubscription information. In operation 217, the UE 700 performs an LAPDN establishment procedure, which will be described later. Upontermination of communication in the LA, a later-described UE requestedPDN disconnection procedure is performed in operation 219.

According to an embodiment of the present disclosure, operation 213 maybe performed differently in the following two cases.

In the case where the current location information (TAI) about the UE700 is included in the updated LA PDN subscription information but theUE 700 does not have an LA PDN context related to the current locationinformation (TAI), the UE 700 starts an LA entry procedure by a UErequested PDN connectivity procedure. On the other hand, in the casewhere the current location information (TAI) about the UE 700 is notincluded in the updated LA PDN subscription information but the UE 700has an LA PDN context related to the current location information (TAI),the UE 700 starts a UE requested PDN disconnection procedure.

With reference to FIGS. 3A to 4, the LA PDN establishment procedureperformed in operation 217 of FIG. 2 will be described. Beforedescribing the LA PDN establishment procedure, triggering of the LA PDNestablishment procedure will first be described below.

FIG. 3A illustrates a triggering method in an LA PDN establishmentprocedure according to an embodiment of the present disclosure.

Referring to FIG. 3A, the UE 700 first performs an initial attachprocedure defined in section 5.3.2.1 of3GPP TS 23.401 in operation 301.The MME 300 downloads subscription information about the UE 700 from theHSS 200 in the initial attach procedure.

In operation 303, the UE 700 determines whether its current locationinformation (TAI) is included in an LA PDN context. In the presence ofthe current location information (TAI) in the LA PDN context, the UE 700starts a UE requested PDN connectivity procedure defined in section5.10.2 of3GPP TS 23.401. If the UE 700 is allowed to establish an LAPDN, the MME 300 checks the subscription information about the UE 700.The above-described procedure of FIG. 3A may be understood as anattach-triggered PDN establishment procedure.

FIG. 3B illustrates a triggering method in an LA PDN establishmentprocedure according to an embodiment of the present disclosure.

Referring to FIG. 3B, when the UE 700 enters an LA in idle state inoperation 311, the UE 700 performs, for example, a Tracking Area Update(TAU) procedure using an active flag as defined in sections 5.5.5.1 &5.3.3.2 of3GPP 23.401. The MME 300 downloads LA PDN subscriptioninformation from an old MME (not shown) used before the UE 700 entersthe LA or the HSS 200. The UE 700 determines whether its currentlocation information (TAI) (the TAI includes a TA Code (TAC) indicatingthe current location of the UE 700) is included in the LA PDNsubscription information. In the presence of the current locationinformation (TAI) in the LA PDN subscription information, the UE 700starts the UE requested PDN connectivity procedure defined in section5.10.2 of3GPP TS 23.401 in operation 313.

If the UE 700 is allowed to establish an LA PDN, the MME 300 checkssubscription information about the UE 700. The above-described procedureof FIG. 3B may be understood as a TAU-triggered PDN establishmentprocedure.

FIG. 3C illustrates a triggering method in an LA PDN establishmentprocedure according to an embodiment of the present disclosure.

Referring to FIG. 3C, when the UE 700 enters an LA in connected state,the UE 700 and the network perform, for example, an S1 handover or X2handover procedure and an accompanying TAU procedure defined in sections5.3.3.1 & 5.3.3.2 of3GPP 23.401 in operation 321. The MME 300 downloadsLA PDN subscription information from an old MME (not shown) used beforethe UE 700 enters the LA or the HSS 200. The UE 700 determines whetherits current location information (TAI) is included in the LA PDNsubscription information. In the presence of the current locationinformation (TAI) in the LA PDN subscription information, the UE 700starts the UE requested PDN connectivity procedure defined in section5.10.2 of3GPP TS 23.401 in operation 323. If the UE 700 is allowed toestablish an LA PDN, the MME 300 checks subscription information aboutthe UE 700. The above-described procedure of FIG. 3C may be understoodas a handover & TAU-triggered PDN establishment procedure.

When the UE 700 enters an LA, the LA PDN establishment procedure may beinitiated by one of the above three triggering methods according to anembodiment of the present disclosure. In the LA PDN establishmentprocedure, the MME 300 checks the LA PDN subscription informationreceived from the HSS 200. If the LA PDN subscription information isvalid, the MME 300 creates an LA PDN session with the L-GW 500 (that is,the P-GW). The MME 300 starts to establish an LA PDN bearer using an LAPDN context. The LA PDN context includes LA PDN information, a TA list,and an LA ID. After the LA PDN bearer is established, the eNB 600maintains the LA PDN bearer context.

FIG. 4 is a diagram illustrating a signal flow for an LA PDNestablishment procedure according to an embodiment of the presentdisclosure.

Referring to FIG. 4, the UE 700 determines whether its current locationinformation (TAI) is included in LA PDN subscription information inoperation 401. In an embodiment of the present disclosure, it is assumedthat the current location information (TAI) about the UE 700 is includedin the LA PDN subscription information. In operation 403, the UE 700determines to start an LA PDN connectivity procedure and transmits an LAPDN connectivity request to the MME 300 by a Non Access Stratum (NAS)transport message.

The MME 300 determines whether the current location information (TAI)about the UE 700 is included in an LA PDN context in operation 405. Inan embodiment of the present disclosure, it is assumed that the currentlocation information (TAI) is included in the LA PDN context. Inoperation 407, the MME 300 accepts the LA PDN connectivity requestreceived from the UE 700 in operation 403 and transmits a create sessionrequest message along with the LA PDN context to the S-GW 400.

The S-GW 400 transmits a create session request message along with theLA PDN context to the L-GW 500 (that is, the P-GW) in operation 409. Inoperation 411, the L-GW 500 (that is, the P-GW) which performs a PCCfunction creates a session for connection establishment for the UE 700and transmits a create session response message to the S-GW 400 inoperation 413. The S-GW 400 transmits a create session response messageindicating reception of the create session response message in operation411 to the MME 300 in operation 415. In operation 417, the MME 300allows LA PDN establishment for the UE 700 and transmits a bearer setuprequest along with the LA PDN context to the eNB 600 according to anembodiment of the present disclosure.

Subsequently, the eNB 600 transmits a Radio Resource Control (RRC)connection reconfiguration message to the UE 700 in operation 419 andreceives an RRC connection reconfiguration complete message from the UE700 that has completed RRC connection reconfiguration in response to theRRC connection reconfiguration message in operation 421. In operation423, the eNB 600 transmits a bearer setup response message to the MME300 in response to the bearer setup request message received inoperation 417.

In operation 425, the UE 700 transmits a direct transfer messageindicating PDN connection completion to the eNB 600. The eNB 600transmits a message indicating the PDN connection completion of the UE700 to the MME 300 in operation 427. The MME 300 transmits a messagerequesting bearer establishment for the UE 700 that has completed thePDN connection establishment to the S-GW 400 in operation 429 and theS-GW 400 establishes a bearer and transmits a response messageindicating completion of the bearer establishment to the MME 300 inoperation 431.

In operation 433, when determining that the bearer establishment iscompleted, the MME 300 transmits a notify request message to the HSS200. The HSS 200 transmits a notify response message to the MME 300 inoperation 435.

In the above-described LA PDN establishment procedure illustrated inFIG. 4, the other operations except operations 401, 405, and 417 may beperformed in the same manner as the UE requested PDN connectivityprocedure defined in section 5.10.2 of3GPP TS 23.401.

After the LA PDN connection establishment is completed according to theprocedure of FIG. 4, the UE 700 may move to another eNB inside oroutside the LA in active mode.

A source eNB to which the LA PDN connection has been establishedtransmits an LA PDN handover context for the UE 700 to a target eNB towhich the UE has moved (has performed handover). The LA PDN handovercontext includes the LA PDN context and an LA PDN bearer context. The LAPDN bearer context is a context including bearer configurationinformation for transmitting traffic received via an LA PDN connection.The LA PDN context and the LA PDN bearer context may be transmitted byan X2 handover request or S1 handover request message well known to theEPS. The S1 handover request message is transmitted from the source eNBto the target eNB through the MME 300.

With reference to FIGS. 5 and 6, a procedure for transmitting an LA PDNcontext during handover according to an embodiment of the presentdisclosure will be described below.

FIG. 5 is a diagram illustrating a signal flow for a procedure fortransmitting an LA PDN context during X2 handover according to anembodiment of the present disclosure. It is assumed herein that the UE700 in connected state moves from a source eNB 600 a to a target eNB 600b in the same LA.

Referring to FIG. 5, the UE 700 that moves to the target eNB 600 btransmits a measurement report to the source eNB 600 a in operation 501and the source eNB 600 a checks whether current location information(TAI) about the UE 700 is included in an LA PDN context in operation503. In an embodiment of the present disclosure, it is assumed that thecurrent location information (TAI) about the UE 700 is included in theLA PDN context.

In operation 505, the source eNB 600 a transmits a handover requestmessage including an LA PDN handover context to the target eNB 600 b.The LA PDN handover context includes an LA PDN context and an LA PDNbearer context. The LA PDN context includes an LA ID and a TA list, andthe LA PDN bearer context includes related bearer IDs (for example,Evolved Radio Access Bearer (E-RAB) IDs).

A bearer configuration is modified and a communication path is switchedfrom the source eNB 600 a to the target eNB 600 b in operations 507 to523 according to a known X2 handover procedure of the3GPP EPS.Therefore, operations 507 to 523 are not described herein in detail.

FIG. 6 is a diagram illustrating a signal flow for a procedure fortransmitting an LA PDN context during S1 handover according to anembodiment of the present disclosure. It is assumed herein that the UE700 in connected state moves from the source eNB 600 a to the target eNB600 b in the same LA.

Referring to FIG. 6, the UE 700 that moves to the target eNB 600 btransmits a measurement report to the source eNB 600 a in operation 601,and the source eNB 600 a checks whether current location information(TAI) about the UE 700 is included in an LA PDN context in operation603. In an embodiment of the present disclosure, it is assumed that thecurrent location information (TAI) about the UE 700 is included in theLA PDN context.

In operation 605, the source eNB 600 a transmits a handover requestmessage including an LA PDN handover context to the target eNB 600 b.The LA PDN handover context includes an LA PDN context, an LA PDN bearercontext, and a bearer information list (for example, a SystemArchitecture Evolution (SAE) Bearer Information List in the EPS). The LAPDN context includes an LA ID and a TA list.

Table 1 below illustrates a transparent container including the LA PDNhandover context of operation 605.

TABLE 1 IE/Group IE type and Semantics Assigned Name Presence Rangereference description Criticality Criticality RRC M OCTET — — ContainerSTRING SAE M YES Ignore Bearers information List > SAE 1 to <max EACHIgnore Bearers no of information SAE item bearers> >> SAE M BIT — —Bearer ID STRING (SIZE(8)) >> DL O 9.2.3.14 forwarding

Handover-related signaling is performed between the source eNB 600 a andthe target eNB 600 b and between a source MME 300 a and a target MME 300b in operations 607 to 633 according to a known S1 handover procedure ofthe3GPP EPS. Therefore, operations 607 to 633 are not described hereinin detail.

Now, a description will be given of an LA PDN disconnection procedureaccording to an embodiment of the present disclosure.

When the UE 700 moves in an idle state or performs a handover procedurein a connected state, the LA PDN disconnection procedure may beperformed. The UE 700 and the network perform a TAU procedure during theLA PDN disconnection procedure.

FIG. 7 is a diagram illustrating a signal flow for an LA PDNdisconnection procedure according to an embodiment of the presentdisclosure.

Referring to FIG. 7, the UE 700 starts a TAU procedure for LA PDNdisconnection in operation 701 and transmits a TAU request message tothe eNB 600 in operation 703. In operation 705, the eNB 600 transmits aTAU request message to the MME 300. The TAU procedure is performed alongwith an S-GW change, as defined in section 5.3.3.1 of3GPP TS 23.401 inoperation 707.

In operation 709, the MME 300 checks whether the current locationinformation (TAI) about the UE 700 is included in an LA PDN TA list. Inthe absence of the current location information (TAI) about the UE 700in the LA PDN TA list, the MME 300 triggers LA PDN disconnection. Thus,the MME 300 transmits a delete session request message to the S-GW 400in operation 711. The S-GW 400 transmits a delete session requestmessage to the L-GW 500 in operation 713. When the L-GW 500 deletes asession, the L-GW 500 transmits a delete session response message to theS-GW 400 in operation 715 and then performs a PCC function along withthe session deletion in operation 717. Upon receipt of the sessiondelete response message in operation 715, the HSS 200 transmits asession delete response message to the MME 300 in operation 719. Inoperation 721, the MME 300 transmits a TAU accept message to the UE 700.The UE 700 transmits a TAU complete message to the MME 300 in operation723.

An LA PDN disconnection procedure according to an embodiment of thepresent disclosure will be described below.

The MME 300 and the UE 700 may maintain an LA PDN context untilexpiration of an LA PDN context retain timer, rather than release an LAPDN connection according to an embodiment of the present disclosure. Inthe present disclosure, this operation mode is defined as LA PDN awaymode.

FIG. 8 is a diagram illustrating a signal flow for a deferred LA PDNdisconnection procedure according to an embodiment of the presentdisclosure.

Referring to FIG. 8, operations 801 to 807 are performed in the samemanner as operations 701 to 707 of FIG. 7 and thus will not be describedherein. In operation 809, the MME 300 determines whether currentlocation information (TAI) about the UE 700 is included in an LA PDN TAlist. In the absence of the current location information (TAI) about theUE 700, the MME 300 determines to switch to the LA PDN away mode andperforms one of the following operations 1), 2), and 3) in relation todeferred LA PDN disconnection according to the state of the LA PDNcontext retain timer.

-   -   1) Registration of the LA PDN context retain timer: if the        deferred LA PDN disconnection is enabled, the MME 300 defers        release of an LA PDN connection. That is, the MME 300 registers        the LA PDN context retain timer instead of releasing the LA PDN        connection.    -   2) Deletion of the LA PDN context retain timer: if the UE 700        completes a TAU procedure before expiration of the LA PDN        context retain timer in an LA, the MME 300 deletes the LA PDN        context retain timer.    -   3) Expiration of the LA PDN context retain timer: if the LA PDN        context retain timer expires without the TAU procedure of the UE        700 in the LA, the MME 300 performs the LA PDN disconnection        procedure.

The MME 300 transmits a TAU accept message to the UE 700 in operation811 and the UE 700 transmits a TAU complete message to the MME 300 inoperation 813. The TAU accept message includes an LA PDN context retaincommand and information about the LA PDN context retain timer. The UE700 may be aware that the deferred LA PDN disconnection procedure isperformed by checking the information included in the TAU acceptmessage.

If the embodiment of FIG. 8 is implemented, even though the UE 700 movesout of the LA, when the MME 300 decides to maintain the LA PDNconnection, the MME 300 may set the state of the LA PDN context to theLA PDN away mode. In this case, the MME 300 may transmit the TAU acceptmessage with, for example, an LA PDN maintain action code indicator asthe LA PDN context retain command and the value of the timer as theinformation about the LA PDN context retain timer to the UE 700 inoperation 811.

In an embodiment of the present disclosure, if the UE 700 returns to theLA in the LA PDN away mode, an LA PDN reconnection procedure may beperformed. Then the MME 300 transmits an LA PDN context and a stored LAPDN bearer context during handover of the UE 700 in connected state orupon receipt of a service request from the UE 700 in idle state.

FIG. 9 is a diagram illustrating a signal flow for an LA PDNreconnection procedure according to an embodiment of the presentdisclosure. The LA PDN reconnection procedure is initiated by a servicerequest from the UE 700 in the idle state.

Referring to FIG. 9, the UE 700 returns to an LA in the LA PDN away modeand thus performs a service request procedure to the eNB 600 inoperation 901. The eNB 600 transmits a service request of the UE 700 tothe MME 300 in operation 903. As an example, the service request istransmitted by NAS signaling. In operation 905, the MME 300 and the HSS200 perform an authentication security procedure. If the MME 300determines that an LA PDN connection is still in the LA PDN away mode inan embodiment of the present disclosure, the MME 300 transmits an S1initial context setup request message including the LA PDN context andthe LA bearer context to the eNB 600 in operation 907.

In operation 911, the UE 700 and the eNB 600 perform a radio bearersetup procedure related to an LA PDN connection. The eNB 600 transmitsan initial context setup complete message to the MME 300 in operation913 and the MME transmits a bearer modify request message for LA PDNreconnection to the S-GW 400 in operation 915. In operation 917, theS-GW 400 transmits the bearer modify request message to the L-GW 500.The L-GW 500 performs a PCC function for the LA PDN reconnection inoperation 919 and transmits a response message to the bearer modifyrequest message to the S-GW 400 in operation 921. The S-GW 400 transmitsa response message to the bearer modify request message received inoperation 915 to the MME 300 in operation 923.

FIG. 10 is a diagram illustrating a signal flow for an LA PDNreconnection procedure according to an embodiment of the presentdisclosure. In the embodiment of FIG. 10, the LA PDN reconnectionprocedure is triggered by handover of the UE 700 in the connected state.

Referring to FIG. 10, as the UE 700 returns to the LA in the LA PDN awaymode, the UE 700 performs a handover procedure in connected mode inoperation 1001. The handover procedure is performed from a source eNB(S-eNB) outside the LA to a target eNB (T-eNB) within the LA, includinga TAU procedure. In operation 1003, the MME 300 determines whethercurrent location information (TAI) about the UE 700 is included in an LAPDN context before expiration of the LA PDN context retain timer. In thepresence of the current location information (TAI) about the UE 700 inthe LA PDN context, the MME 300 determines whether the state of an LAPDN is the LA PDN away mode. If both of the conditions are satisfied,the MME 300 decides to reconfigure (reconnect) an LA PDN bearer. If theMME 300 decides to reconfigure the LA PDN bearer in operation 1003, theMME 300 transmits a bearer setup request message including an LA PDNcontext and an LA bearer context to the T-eNB 600 b in operation 1005.Subsequently, an RRC reestablishment procedure is performed between theUE 700 and the T-eNB 600 b in operations 1007 and 1009. In operation1011, the T-eNB 600 b transmits a bearer setup response messageindicating the bearer reconfiguration to the MME 300.

FIG. 11 is a block diagram of a UE according to an embodiment of thepresent disclosure.

Referring to FIG. 11, the UE includes a transmitter 1110 and a receiver1130, which respectively transmit and receive messages according to thevarious embodiments of the present disclosure illustrated in FIGS. 1A to10 in order to establish, maintain, release, or reestablish an LA PDNconnection with an eNB through a wireless network. The UE furtherincludes a controller 1150 that controls the transmission and receptionof messages according to the various embodiments of the presentdisclosure illustrated in FIGS. 1A to 10 to and from an eNB in order toestablish, maintain, release, or reestablish an LA PDN connection andprovides overall control to the UE so that the UE may conductcommunication in each communication state of an LA PDN.

FIG. 12 is a block diagram of an eNB according to an embodiment of thepresent disclosure.

Referring to FIG. 12, the eNB includes a first communication interface1210 for transmitting and receiving messages to and from a UE through awireless network according to the various embodiments of the presentdisclosure illustrated in FIGS. 1A to 10 during establishment,maintenance, release, or reestablishment of an LA PDN connection in theUE 700, and a second communication interface 1230 for transmitting andreceiving signals to and from other network entities of an EPS systemsuch as another eNB or an MME via a predetermined communicationinterface. The eNB further includes a controller 1250 that controls thetransmission and reception of the various messages as described above.The eNB transmits and receives messages for establishment, maintenance,release, or reestablishment of an LA PDN connection in the UE 700 inpredetermined procedures and participates in procedures such as currentlocation information check, TAU, bearer establishment, and handover of aUE in the LA PDN based on the transmitted and received messagesaccording to the various embodiments of the present disclosureillustrated in FIGS. 1A to 10.

While not shown, an MME may also be configured to include acommunication interface for transmitting and receiving messages to andfrom a UE through a wireless network according to the variousembodiments of the present disclosure illustrated in FIGS. 1A to 10during establishment, maintenance, release, or reestablishment of an LAPDN connection in the UE, and a controller for controlling relatedoperations.

While the present disclosure has been shown and described with referenceto various embodiments thereof, it will be understood by those skilledin the art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the present disclosure asdefined by the appended claims and their equivalents.

1. A method for establishing a packet data network (PDN) connection by auser equipment (UE) in a wireless communication system, the methodcomprising: receiving subscription information associated with a localarea (LA) PDN from an operator server; determining whether currentlocation information about the UE is included in the subscriptioninformation; and performing an establishment procedure for the LA PDN,if the current location information about the UE is included in thesubscription information.
 2. The method of claim 1, wherein the currentlocation information about the UE includes a current tracking area(indication (TAI) of the UE.
 3. The method of claim 1, furthercomprising, if the subscription information is updated, receiving, froma mobility management entity (MME), information indicating that the LAsubscription information is updated.
 4. The method of claim 1, whereinthe subscription information includes at least one of a tracking area(TA) list, an LA access point Name (LA APN), an LA identifier (LA ID),additional information, and existing PDN configuration data.
 5. Themethod of claim 1, wherein the establishment procedure for the LA PDN istriggered by one of an initial attach procedure, a TA update (TAU)procedure, and a handover and TAU procedure.
 6. The method of claim 1,wherein the performing of the establishment procedure comprisestransmitting a connectivity request message including the currentlocation information about the UE to an MME, and wherein the MMEperforms a PDN connectivity procedure, if the current locationinformation about the UE is included in the subscription information. 7.A user equipment (UE) for establishing a packet data network (PDN)connection in a wireless communication system, the UE comprising: areceiver configured to receive data through a network; and a controllerconfigured to receive subscription information associated with a localarea (LA) PDN from an operator server, to determine whether currentlocation information about the UE is included in the subscriptioninformation, and to perform an establishment procedure for the LA PDN,if the current location information about the UE is included in thesubscription information.
 8. The UE of claim 7, wherein the currentlocation information about the UE includes a current tracking areaindication (TAI) of the UE.
 9. The UE of claim 7, wherein if thesubscription information is updated, the controller further controlsreceiving, from a mobility management entity (MME), informationindicating that the subscription information is updated.
 10. The UE ofclaim 7, wherein the subscription information includes at least one of atracking area (TA) list, an LA access point name (LA APN), an LAidentifier (LA ID), additional information, and existing PDNconfiguration data.
 11. The UE of claim 7, wherein the establishmentprocedure for the LA PDN is triggered by one of an initial attachprocedure, a TA update (TAU) procedure, and a handover and TAUprocedure.
 12. The UE of claim 7, further comprising a transmitterconfigured to transmit a message for LA PDN establishment to a network,wherein the controller is configured to controls transmission of aconnectivity request message including the current location informationabout the UE to an MME, and wherein the MME performs a PDN connectivityprocedure, if the current location information about the UE is includedin the subscription information.
 13. A method for updating subscriptioninformation about a user equipment (UE) in a wireless communicationsystem, the method comprising: receiving subscription informationassociated with a local area (LA) packet data network (PDN) from anoperator server; determining whether current location information aboutthe UE is included in context information including a tracking area (TA)list of the UE; and transmitting information indicating an update of thesubscription information to the UE, if the current location informationabout the UE is included in the information including the TA list. 14.The method of claim 13, wherein the operator server provides the updatedsubscription information to the UE, if the current location informationabout the UE is included in the context information associated with theLA PDN.
 15. A network entity in a wireless communication system, thenetwork entity comprising: a communication interface configured tocommunicate with other network entity; and a controller configured, tocontrol reception of subscription information associated with a localarea (LA) packet data network (PDN) from an operator server if thesubscription information about the UE is updated, to determine whethercurrent location information about the UE is included in contextinformation including a tracking area (TA) list of the UE, and tocontrol transmission of information indicating the update of thesubscription information to the UE if the current location informationabout the UE is included in the context information including the TAlist.
 16. The network entity of claim 15, wherein the operator serverprovides the updated subscription information to the UE, if the currentlocation information about the UE is included in the context informationassociated with the LA PDN.
 17. A communication method of a base station(BS) in a wireless communication system, the communication methodcomprising: if a user equipment (UE) performs handover to a target BSwithin a local area (LA) in a connected state, determining whethercurrent location information about the UE is included in contextinformation associated with a LA packet data network (PDN); andtransmitting a handover request message including the contextinformation related to the handover to the target BS, if the currentlocation information about the UE is included in the contextinformation.
 18. The communication method of claim 17, wherein the BSand the target BS are located in the same LA.
 19. The communicationmethod of claim 17, wherein the context information related to thehandover includes an LA PDN context and an LA PDN bearer context, thecontext information including an LA identifier (ID) and a tracking area(TA) list and the LA PDN bearer context including related bearer IDs.20. The communication method of claim 17, wherein the handover is one ofan X2 handover and an S1 handover in an evolved packet system (EPS). 21.A base station (BS) for supporting handover of a user equipment (UE) ina wireless communication system, the BS comprising: a communicationinterface configured to transmit and receive messages related to thehandover of the UE; and a controller configured, if the UE performshandover to a target BS within a local area (LA) in a connected state,to determine whether current location information about the UE isincluded in context information associated with a LA packet data network(PDN), and to transmit a handover request message including the contextinformation related to the handover to the target BS, if the currentlocation information about the UE is included in the contextinformation.
 22. The BS of claim 21, wherein the BS and the target BSare located in the same LA.
 23. The BS of claim 21, wherein the contextinformation related to the handover includes an LA PDN context and an LAPDN bearer context, the LA PDN context including an LA identifier (ID)and a tracking area (TA) list and the LA PDN bearer context includingrelated bearer IDs.
 24. The BS of claim 21, wherein the handover is oneof an X2 handover and an S1 handover in an evolved packet system (EPS).25. A method for releasing a packet data network (PDN) connection by anetwork entity that manages mobility of a user equipment (UE) in awireless communication system, the method comprising: receiving atracking area update (TAU) request from the UE; determining whethercurrent location information about the UE is included in a TA listassociated with a local area (LA) PDN; and performing an LA PDNdisconnection procedure, if the current location information about theUE is included in the TA list.
 26. A method for releasing a packet datanetwork (PDN) connection by a network entity that manages mobility of auser equipment (UE) in a wireless communication system, the methodcomprising: determining whether current location information about theUE is included in a tracking area (TA) list associated with a local area(LA) PDN; and maintaining context information associated with the LA PDNof the UE until expiration of timer for LA PDN context retain.
 27. Themethod of claim 26, further comprising: receiving a tracking area update(TAU) request message from the UE; and transmitting a TAU accept messageincluding a command for the LA PDN context retain and the timer to theUE.
 28. A method for reestablishing a packet data network (PDN)connection by a network entity that manages mobility of a user equipment(UE) in a wireless communication system, the method comprising:receiving a service request message from the UE that returns to a localarea (LA); transmitting an initial context setup request messageincluding an LA PDN context and an LA bearer context of the UE to a basestation (BS); and transmitting a bearer modify request for LA PDNreconnection of the UE to a serving gateway.
 29. A method forreestablishing a packet data network (PDN) connection by a networkentity that manages mobility of a user equipment (UE) in a wirelesscommunication system, the method comprising: receiving a tracking areaupdate (TAU) request from the UE that performs handover in a connectedstate from a source base station (BS) outside a local area (LA) to atarget BS within the LA; determining whether current locationinformation about the UE is included in context information associatedwith a local area (LA) PDN before expiration of an LA PDN context retaintimer; and transmitting to the target BS a bearer setup requestincluding an LA PDN context and a bearer context, if the currentlocation information about the UE is included in the contextinformation.